Question from the MSR Web Site

Dan Kohn dan@dankohn.com
Fri, 12 Apr 2002 14:33:22 -0700


Thanks so much for the detailed response.

          - dan
--
Dan Kohn <mailto:dan@dankohn.com>
<http://www.dankohn.com/>  <tel:+1-650-327-2600>
Essays announced on <mailto:dankohn-subscribe@yahoogroups.com>=20
=20

-----Original Message-----
From: Consumer [mailto:consumer@cascadedesigns.com]=20
Sent: Friday, April 12, 2002 14:31
To: Dan Kohn
Subject: RE: Question from the MSR Web Site


Dan,
	You are correct, that is indeed the strange question of the day.
Actually, it might be the strange question of the year, but since it's
still
early in 2002 I can't give a definite answer.  Hopefully I can offer an
explanation for what you discovered.  When you filter water, you're
filtering water and anything (dissolved or otherwise) that is in
it--larger
particles such as bacteria and protozoa get filtered out by the ceramic
and
the carbon core takes care of most chemicals and odors.  Smaller stuff
(like
viruses) don't get filtered out, because they're pretty tiny.  (Viruses
can
get killed by treatment with chemical means.)  This filter also won't
take
care of some dissolved things in the water--heavy metals, salt, and
tannins
are just some of the things the filter isn't able to remove.
	So, this would apply to your attempt to filter beer and urine.
Beer
and urine contain a lot of dissolved particles that cannot be removed by
the
carbon of the filter--in urine, for example, there is uric acid and
salt.
While our filters CAN filter saltwater, they aren't desalinizers, so
they
won't remove the salt from the water--in these cases you would still
have
the taste (and odor, if applicable) of saltwater in the filtered water.
This would explain why your filtered urine still had the
smell/appearance of
urine, and it would also apply to the case of the filtered beer.  While
water is water, beer is beer and urine is urine--these substances are
composed of water true enough, but they have a lot of other things
dissolved
in them that make them what they are.  As I previously mentioned, the
filter
isn't able to take care of tannins--tannins are most commonly found in
beverages such as tea, and lend a tint to the water--if you pass water
containing tannins through the filter then the tannins won't get
removed,
and your filtered water will retain the original brownish color of the
water
with tannins.  This would also explain why the filtered urine and beer
still
retained their original appearance, if a little bit diluted. =20
	I assume that your observations were based on appearance and
odor of
the filtered water--the above information would provide explanation for
these . . . . I won't ask if you tasted the filtered substances! =20
	All this being said, I would strongly urge you to replace the
filter
elements (Ceramic element and PES membrane) before using them again, for
maximum protection.
	Hope this makes sense.  If you have additional questions, please
email us back.    =20


Cheers,
Elaine

Elaine Serfass
MSR/Cascade Designs
Customer Service
800-531-9531


-----Original Message-----
From: dan@dankohn.com [mailto:dan@dankohn.com]=20
Sent: Thursday, April 11, 2002 10:59 PM
To: Consumer
Subject: Question from the MSR Web Site


[* Sent to MSR customer service  - dan *]

I suspect this will be your strange question of the day:

I've been a fan of MSR and used the MiniWorks extensively when hiking in
Namibia last month to filter quite dirty water, with sparkling,
tasteless
water being created every time.

My new Waterworks II just arrived today from REI, and as a test, I tried
it
on two rather unusual substances: beer and urine.  Disappointingly, in
both
cases, the result was clearly not pure water (it looked and smelled like
diluted urine and then like sudsy, diluted beer).

Could you please explain to me why this "science experiment" didn't
work,
and yet the WaterWorks is presumably able to filter much smaller
particles
to eliminate dangerous organisms.

And don't worry, I cleaned the filter extensively before packing it away
for
my next trip.

Sincerely,

Dan Kohn
dan@dankohn.com
650-327-2600